Patent GB-548393-A (GB)
Title: Improvements in lathes and other machine tools
IPC: B23Q5/18
Filed: 1941-04-30
Abstract: 548,393. Variable-speed gearing. WARNER & SWASEY CO. April 30, 1941, No. 5616. Convention date, April 30, 1940. [Class 80 (ii)]' [Also in Group XXII] A lathe or other machine tool has a part such as the spindle drive at various speeds for the different operative steps of a work cycle, the speeds being selected or preselected by an indexible member associated with a control device comprising preadjusted stop members coacting with stop means to arrest the indexible member in different predetermined positions correlated to the different steps of the cycle. In the application twelve speeds in either direction by the train shown in Fig. 7. The pulley 36 drives a shaft 37 carrying a splined clutch member 38 engageable either with a gear 42 engaging directly with gear 43 to drive shaft 44 in one direction or with gear 41 which through an idler 45 drives shaft 44 in the opposite direction. A sliding triple gear 47-49 on shaft 44 imparts a three-speed drive to shaft 53 which drives a double gear-sleeve 54, 56 loose on the spindle. A sliding double gear 57, 58 coacts with the gear sleeve to give a two-speed drive from the sleeve to shaft 59 and this shaft is geared to the spindle by a sliding pair 60, 61, thus giving twelve speeds in all. The clutch element 38 is shifted by a yoke actuated by a vertical rock shaft 68, Fig. 2, depending from a member 71 which may be oscillated about a vertical axis by movement in a horizontal plane of a control lever 72. The triple gear on shaft 44 and the two sliding gear pairs on shaft 59 are actuated through lever mechanism connected to pins 80, 83, 90 coacting with a pair of spools 92 splined on a shaft 91 and having a series of thirteen (twelve speeds and a neutral) pairs of co-operating fingers. The spools are separated by a lever 1'09 actuated by movement of the control lever 72 in a vertical plane, a spring bias being normally effective to maintain separation of the spools. When separated the spools are indexed to preselect any required gear and when the spools are moved together the preselected gear is engaged. Indexing may be effected manually from a hand-wheel 96 geared to the spindle 119, Figs. 11 and 13 of a drum indicator which shows spindle speeds and also cutting speeds in feet per minute for different operative steps of a work cycle. The indicator unit also includes automatic mechanism for indexing the spools to obtain a predetermined succession of speed changes. The drum is supported on a ball bearing 126 and its indications are read in a window formed in its housing 118, Fig. 9. The upper part of the drum has spaced slots 138 which may carry numbered blocks 139 which may be successively brought into alignment with a fixed mark 135 when manual indexing of the drum is employed to preselect the required speeds for a work cycle. The upper part of the drum is also fitted with a clutch part 130 coacting with a loose clutch element 140 carrying a roller 141 coacting with a spring- pressed cam member 144 splined to shaft 119. With the roller on the lowest point of the cam, rotation of the shaft 119 is communicated to the drum, but if the latter is locked by mechanism associated with the automatic pre-selecting means then the roller rides up the cam and compresses the spring, after which, when the drum is released, the spring tension causes the drum to be rotated until the roller again engages the low part of the cam. For automatic actuation the unit carries a motor 149, Fig. 11, connected through a friction clutch 151 to a spring-pressed worm shaft 154 driving a worm wheel 155 which may be clutched by actuation of a button 159 to a sleeve 156 connected by gearing 161 to the shaft 119. The sleeve is provided with eight stop-discs 163 corresponding to a possible work cycle of eight steps and the inner circumferences of the discs have thirteen teeth 165, Fig. 12, coacting with a plunger which prevents rotation on the sleeve in one direction. Each disc also carries a stop projection 164, these projections serving to determine the preselecting movement imparted to the spools. The discs may be adjusted by rotation of the hand-wheel 96 to position the lugs according to the speed required for the particular cycle steps and when the required adjustments have been made the setting may be locked by means of a key. In making the settings, pins 167 are successively projected into the path of the respective lugs and the handwheel turned until the required speed for each particular step appears on the indicator drum. A gear segment 174 actuated by movement of the bar 103 has a bearing in the lower part of the drum housing and coacts with a segment 178 forming part of a support carrying pawls 182, 183, Fig. 15, and mounted on a cam shaft 180 carrying a cam 184 and a loose stop drum 185 provided with eight teeth 188. corresponding to an eight-step cycle. Means are provided for adjusting the cam 184 relative to drum 185 according to the number of steps actually required, this adjustment being indicated by a head 195 which is graduated so that at all times it indicates the current operative step at which the machine is functioning. The cam serves to effect release of the drum at the end of a cycle, the drum being then restored by a spring to an initial position against an abutment 191 ready for the first step of the next cycle. The cam drum 185 is provided with eight axially spaced notches in different angular positions corresponding to the teeth 188 and each notch coacts with a stop finger 205 having an arm 208 which when the finger is in its notch projects into the path of the corresponding lug 164. Assuming that. the uppermost stop finger 205 is in the Fig. 12 position and the motor 149 is started the upper disc 163 is rotated until its lug 164 engages the stop finger and stops the sleeve 156. The worm 154 is then moved endwise to disengage the clutch 150. If now the drum 185 is indexed by the bringing together of the spool the next pawl 205a will drop into its notch and the pawl 205 releases the lug 164 so that the clutch 150 is re-engaged and the rotation of sleeve 156 and the stop discs continues until the corresponding lug 164 engages the part 208 of finger 205a whereupon the drive to the sleeve 156 is again interrupted. This procedure continues until all the required operative steps have been performed, the various lugs 164 having been preset to give the required speeds and the indicating drum being rotated by the gearing 121 to indicate these speeds. Locking means consisting of a bolt 209, Fig. 14, coacting with openings in the indicating drum are arranged normally to lock the drum against rotation. The lock pin is actuated by a bolt 212, Fig. 15, coacting with a cam 214, on a support 215 which when the clutch pin 158 is in engaged position is locked by the said pin against movement. When hand indexing of the spools is required, the clutch pin is withdrawn and the member 215 is then. free to rock so that the pin 209 is disengaged and the indicating drum is free to rotate. When the clutch pin 158 is in its engaging position the parts are in the Fig. 15 position with the cam 214 operative to lock the indicating drum. When the control handle is manipulated and the bar 103 is operated to move the spools together, the gear segments 174, 178 are actuated to move the pin 212 off its cam and unlock the indicating drum which is then moved by the action of spring.145. In this way during automatic actuation the drum is locked while the. preselection is effected with the spools separated and only moves to indicate the speed when such speed is engaged by approach movement of the spools. The movement of the control lever to effect approach of the spools also moves the pawl support 179 to engage the pawl 182 with the next tooth 188 and on the following movement of the spools to the (outer) indexing position the stop drum 185 is indexed through one tooth space and the next successive stop 205 is caused to drop into its notch. As each successive stop finger leaves its notch, the corresponding lug 164 is freed and the stop disc travels with the sleeve 156, the clutch 151 being engaged by spring plunger 153. This movement of the sleeve 156 power indexes the spools to preselect the feed for the next step. The shaft 119 is also rotated to tension the spring 145 so that the indicator drum will be rotated to indicate the preselected speed as soon as its bolt 209 is withdrawn. This occurs when at the completion of each step the operator moves the main control lever to move the spools inwards and obtain the preselected speed. This action also moves the pawl 182 into the next tooth 188. The next step is then initiated by engaging the main clutch with the control lever and then the lever is actuated to move the spools outwardly and index the stop drum to its next position. At the end of a predetermined number of steps (up to eight) the cam 184 disengages the pawl 183. This causes a member 222 to releases whichever stop finger is operative, thus releasing drum 185 which is then returned by its spring to the starting position in readiness for another cycle. For manual preselection of the spindle speeds the clutch pin 158 is disengaged and the pin 210 is not operative. The speeds are then preselected by rotating the spools. from the hand wheel, the indicator drum being rotated at the same time to show the preselected speed.